Strain measurement in composite materials using embedded strain gauges

The feasibility of the use of embedded strain gauges for the measurement of internal deformation in laminated composite material has been investigated. The methodology consists in inserting the strain gauges among the layers of the laminate before polymerisation in the oven. High Temperature Carbon Fibre - Epoxy Matrix composite has been used in this study. A Scanning Laser Acoustic Microscope analysis was performed to check whether the embedding technique caused problems of delamination between the gauges and the layers of composite and between the layers. Tensile, bending and InterLaminar Shear Stress (ILSS) evaluation tests were carried out to assess the feasibility of embedded strain gauges to measure the internal deformation in laminate composites The results obtained showed good agreement with theoretical values from simple calculations.